Gas turbine engine and operations

ABSTRACT

An improved gas turbine engine is adapted to include an inlet flow control arrangement disposed in an inlet passage at least between a filter member and a row of Variable Inlet Guide Vanes (VIGV), and adjacent the filter member, to enable pressure loss in the inlet passage and supply reduced amount of inlet air to a compressor to enable the reduction of power output of the gas turbine engine at a low load condition.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to European application 13176146.2 filed Jul. 11, 2013, the contents of which are hereby incorporated in its entirety.

TECHNICAL FIELD

The present disclosure relates to a gas turbine engine, and, more particularly, to a gas turbine engine with improved efficiency and improved emission control of combustion products, such as Nitrogen Oxide gases (NOx), Carbon monoxide (CO), Carbon dioxide (CO₂), Unburned Hydrocarbons (UHC) etc., in exhaust gases, at low load condition.

BACKGROUND

In recent times, with growing concern to protect environment, more and more industries are shifting towards renewable energy sources to produce power, which leads to a requirement for convention power plants to be competitive and to be able to operate at very low load and within constraints of a regulatory environment including limits on the emission of one or more combustion products such as Nitrogen Oxide gases (NOx), Carbon monoxide (CO), Carbon dioxide (CO₂), Unburned Hydrocarbons (UHC) etc., in exhaust gases.

Operating the power plant at low load condition and maintaining emission within the constraints of environment regulatory at the same time is a challenge. Various attempts in this regard have been taken previously, among such, one attempt include reducing inlet air flow by closing Variable Inlet Guide Vanes (VIGV) in the gas turbines or combined cycle power plants.

However, closing the VIGV for reducing the inlet air flow is possible to a certain extent only because after a certain limit the compressor on which the VIGV are configured begins to reach operation limits, and any further closing of the VIGV may lead to aerodynamically unstable operation or damage. Further, reduction of power for enabling the power plant to operate at low load condition may be done by reducing a turbine inlet temperature within the gas turbine. This, however, is constrained by operational limits of the specific combustor or becomes detrimental to the environment regulatory with regard to emission of one or more combustion products, as described above.

Accordingly, there exists a need for an improved gas turbine and operations.

SUMMARY

The present disclosure describes an improved gas turbine engine, that will be presented in the following simplified summary to provide a basic understanding of one or more aspects of the disclosure that are intended to overcome the discussed drawbacks, but to include all advantages thereof, along with providing some additional advantages. This summary is not an extensive overview of the disclosure. It is intended to neither identify key or critical elements of the disclosure, nor to delineate the scope of the present disclosure. Rather, the sole purpose of this summary is to present some concepts of the disclosure, its aspects and advantages in a simplified form as a prelude to the more detailed description that is presented hereinafter.

An object of the present disclosure is to describe an improved gas turbine engine, which may be adaptable in terms of being modified for being operable at low load condition and within constraints of a regulatory environment on emission of one or more combustion products such as Nitrogen Oxide gases (NOx), Carbon monoxide (CO), Carbon dioxide (CO₂), Unburned Hydrocarbons (UHC) etc., in exhaust gases. Another object of the present disclosure is to describe an improved gas turbine, which is convenient to use in an effective and economical way. Various other objects and features of the present disclosure will be apparent from the following detailed description and claims.

The above noted and other objects, in one aspect, may be achieved by an improved gas turbine engine of a power plant. The gas turbine engine includes inlet and exhaust passages. The inlet passage is adapted to receive and direct inlet air to a compressor to compress and supply the inlet air to a combustor to produce gas to drive a turbine. Further, the exhaust passage is adapted to release exhaust gas from the turbine. The gas turbine engine further includes a filter member, at least a row of Variable Inlet Guide Vanes (VIGV) and an inlet air flow control arrangement. The filter member is disposed in the inlet passage to filter the inlet air. The VIGV is adapted to be configured on the compressor. Furthermore, the inlet air flow control arrangement is adapted to be detachably disposed at least between the filter member and the row of VIGV, and adjacent to the filter member. The detachable attachment enables removing of the inlet air flow control arrangement, whenever not required. The at least one of the VIGV and the air inlet flow control arrangement are configured to be selectively operable and controllable, upon requirement, to at least partially close the inlet passage to modulate and create predetermined required pressure loss in the inlet passage in order to supply reduced amount of the inlet air to the compressor to enable the reduction of power output of the gas turbine engine preferably at part load or at low load condition.

In one embodiment of the present disclosure, the gas turbine engine may further include a heating member adapted to be configured in the inlet passage to heat the inlet air to enable, in combination with the pressure loss in the inlet passage, the reduction of power output of the gas turbine engine to obtain the low load condition.

In one embodiment of the present disclosure, the inlet air flow control arrangement, either independently or in combination with the heating member, under the low load condition of the gas turbine engine, enables reduction of emission of combustion products with the exhaust gas from the exhaust passage.

In one embodiment of the present disclosure, the inlet air flow control arrangement is adapted to be configured to maintain the direction of flow of inlet air such downstream of the VIGV receives axial inflow. In another embodiment of the present disclose, the inlet air flow control arrangement is adapted to be configured to change the direction of flow of the inlet air such that incidence of the inlet air at the VIGV leading edge is reduced in order to provide favorable flow conditions at the compressor inlet.

In one embodiment of the present disclosure, the gas turbine engine may include a control system adapted and configured to control the inlet air flow control arrangement.

In one embodiment of the present disclosure, the gas turbine engine may further include an exhaust gases air flow control arrangement adapted to be detachably disposed in the exhaust passage to increase pressure and temperature of the exhaust gas exiting from the turbine. In one example form, in combined cycle power plants having the gas turbine engine and Heat Recovery Steam Generator (HRSG), the exhaust gases flow control arrangement is adapted to be detachably disposed in the exhaust passage, downstream of the HRSG. The detachable attachment enables removing of the exhaust gases flow control arrangement, whenever not required.

These together with the other aspects of the present disclosure, along with the various features of novelty that characterize the present disclosure, are pointed out with particularity in the present disclosure. For a better understanding of the present disclosure, its operating advantages, and its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated exemplary embodiments of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages and features of the present disclosure will be better understood with reference to the following detailed description and claims taken in conjunction with the accompanying drawing, wherein like elements are identified with like symbols, and in which:

FIG. 1 illustrates an example block diagram of a gas turbine engine, in accordance with an exemplary embodiment of the present disclosure; and

FIG. 2 illustrates an example gas turbine engine portion depicting variable positions of an inlet air flow control arrangement, in accordance with an exemplary embodiment of the present disclosure.

Like reference numerals refer to like parts throughout the description of several views of the drawings.

DETAILED DESCRIPTION

For a thorough understanding of the present disclosure, reference is to be made to the following detailed description, including the appended claims, in connection with the above described drawings. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be apparent, however, to one skilled in the art that the present disclosure can be practiced without these specific details. In other instances, structures and apparatuses are shown in block diagrams form only, in order to avoid obscuring the disclosure. Reference in this specification to “one embodiment,” “an embodiment,” “another embodiment,” “various embodiments,” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. The appearance of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Moreover, various features are described which may be exhibited by some embodiments and not by others. Similarly, various requirements are described which may be requirements for some embodiments but may not be of other embodiment's requirement.

Although the following description contains many specifics for the purposes of illustration, anyone skilled in the art will appreciate that many variations and/or alterations to these details are within the scope of the present disclosure. Similarly, although many of the features of the present disclosure are described in terms of each other, or in conjunction with each other, one skilled in the art will appreciate that many of these features can be provided independently of other features. Accordingly, this description of the present disclosure is set forth without any loss of generality to, and without imposing limitations upon, the present disclosure. Further, the relative terms, such as “first,” “second,” “third” and the like, herein do not denote any order, elevation or importance, but rather are used to distinguish one element from another. Further, the terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.

Referring now to FIGS. 1 and 2, examples of an improved gas turbine engine 100, are illustrated in accordance with an exemplary embodiment of the present disclosure. FIG. 1 illustrates an example block diagram whereas FIG. 2 illustrates an example component view of a portion of the gas turbine engine 100. In as much as the construction and arrangement of the gas turbine engine 100, various associated elements may be well-known to those skilled in the art, it is not deemed necessary for purposes of acquiring an understanding of the present disclosure that there be recited herein all of the constructional details and explanation thereof. Rather, it is deemed sufficient to simply note that as shown in FIGS. 1 and 2, in the gas turbine engine 100, only those components are shown that are relevant for the description of various embodiments of the present disclosure.

As shown in FIG. 1, a block diagram of the gas turbine engine 100 includes inlet and exhaust passages 102, 104. The inlet passage 102 is adapted to receive inlet air from the atmosphere or any other suitable source. The inlet passage 102 includes a filter member 112 disposed therewithin to filter inlet air to provide protection against the effects of contaminated inlet air. Different types of contaminants in the inlet air from the varying environments can cause several types of problems that negatively impact the reliability, availability, and time between overhauls of the gas turbine engine's 100 internal components. Foremost purpose of the filter member 112 is to clean the inlet air to meet the operational goals of the machine and, secondarily, to maintain its filtration efficiency. Specific designs of the filter member 112 may be adapted as per the requirement to protect against particles of various sizes and composition.

The gas turbine engine 100 further includes a compressor 106, various rows of stator vanes 106 a configured on the compressor, a combustor 108 and a turbine 110. The inlet air from the inlet passage 102 is directed to the compressor 106. The inlet air in the compressor 106 is compressed and supplied to the combustor 108 to produce gas. The gas from the combustor 108 is directed through the stator vanes 106 a to drive the turbine 110. Further, the exhaust passage 104 is adapted to release exhaust gas from the turbine 110. The gas turbine engine 100 is adapted and configured to be operable at varying load conditions, i.e. at full-load condition and low-load or part-load condition.

For enabling such operation conditions, the gas turbine engine 100 includes at least a row of Variable Inlet Guide Vanes (VIGV) 114 and an inlet air flow control arrangement 116. The VIGV 114 and the inlet air flow control arrangement 116 are adapted to control the inlet air flow and quantity that is required to be directed into the compressor 106 for combustion purpose depending upon requirement of gas turbine engine 100 operations, i.e. low-load condition or full-load condition. The at least one row of VIGV 114 is adapted to be configured on the compressor 106 before the various rows of stator vanes 106 a.

In one embodiment of the present disclosure, the inlet air flow control arrangement 116 is adapted to be detachably disposed between the filter member 112 and the row of VIGV 114 at any suitable location. In another embodiment of the present disclosure, the inlet air flow control arrangement 116 is adapted to be detachably disposed adjacent to the filter member 112. The detachable attachment enables removing of the inlet air flow control arrangement 116, whenever not required at the disclosed positions.

In an example FIG. 2, the inlet air flow control arrangement 116 is shown to be disposed at three different locations between the filter member 112 and the row of VIGV 114 that may be selected by the user as per system requirement. At a first location, the inlet air flow control arrangement 116 is shown to be disposed between the filter member 112 and the row of VIGV 114 with proximity to the filter member 112 and reasonably distal from the row of VIGV 114. At a second location, the inlet air flow control arrangement 116 is shown to be disposed between the filter member 112 and the row of VIGV 114 at substantially centralized position to both. At third location, the inlet air flow control arrangement 116 is shown to be disposed between the filter member 112 and the row of VIGV 114 with proximity to the row of VIGV 114 and reasonably distal from the filter member 112. However, without departing from the scope of the present disclosure, the inlet air flow control arrangement 116 may be disposed at any preferred locations between the filter member 112 and the row of VIGV 114 depending upon the gas turbine engine 100 operating conditions, apart from the disclosed ones. Further, as per the another embodiment, not as such shown in figures, the inlet air flow control arrangement 116 may be detachably disposed adjacent to the filter member 112 at any preferred locations depending upon the gas turbine engine 100 operating conditions. For example, the placement of the inlet air flow control arrangement 116 may be at front side of the filter member 112, or may be behind/backside of the filter member 112, within the inlet passage 102.

The gas turbine engine 100, while operating at the low-load condition, the at least one of the VIGV 114 and the air inlet flow control arrangement 116 are configured to be selectively operable to at least partially close the inlet passage 102. That is, the VIGV 114 and the air inlet flow control arrangement 116 may be combinedly or separately operated to close the inlet passage 102 to substantially full extent. This enables modulation of the pressure loss to reach at a predetermined level in the inlet passage 102 and reduces the amount of inlet air supply to the compressor 106 to enable the reduction of power output of the gas turbine engine 100 at the low load condition. The predetermined level of the pressure loss may be selected upon the power output requirement at any particular time level during operation of power plants. Normally, in conventional gas turbine engines as found nowadays, intake passage and other elements disposed therein generally create pressure loss, which are not required but can't be avoided. However, the present disclosure utilizes means of maximizing the intake pressure loss intentionally, and the amount of such pressure loss may be fully controllable as per the requirement of the gas turbine engine 100 and working thereof in the low load condition. Such means in one embodiment is the air inlet flow control arrangement 116, which may be fully controllable selectively operable, upon requirement, to close the inlet passage 102 up to a level at which required pressure loss may be obtained.

Further, when required to operate the gas turbine engine 100 at full load condition, the air inlet flow control arrangement 116 may be removed from the inlet passage 102, and the at least one of the VIGV 114 may be opened to maximum to decrease the pressure loss and supply sufficiently higher amount of the inlet air to the compressor 106 to enable the increase in power output of the gas turbine engine 100.

In one embodiment of the present disclosure, the inlet air flow control arrangement 116 may be adapted to maintain the direction of flow of the inlet air such that downstream of the VIGV 114 receives axial inflow. In other words, the direction of flow of the inlet air remains unchanged with the insertion of the inlet air flow control arrangement 116 in the inlet passage 102. Further, in another embodiment, upon requirement, the inlet air flow control arrangement 116 may be adapted to change the direction of flow of the inlet air such that incidence of the inlet air at the VIGV 114 leading edge is reduced.

The gas turbine engine 100 may further include a heating member 118 adapted to be configured in the inlet passage 102. In FIG. 1, the heating member 118 is shown to be disposed between the filter member 112 and the inlet air flow control arrangement 116. However, without departing from the scope of the present disclosure, the heating member 118 may be disposed at any location which is capable of heating the inlet air entering the compressor 106. The heating member 118 may be adapted to be operable during the low load operation condition of the gas turbine engine 100. Specifically, during the low load operation condition, when it is required to heat the inlet air to enable the reduction of power output of the gas turbine engine 100, the heating member 118 in combination with the air inlet flow control arrangement 116 manage the pressure loss in the inlet passage 102. The inlet air flow control arrangement 116, in combination with the heating member 118, is capable of reducing intake pressure by increasing the inlet pressure loss in turn reducing intake mass flow of inlet air while maintaining the volume of the mass flow of the intake air without affecting the combustor 108 or its chamber's operating conditions. Further, the inlet air flow control arrangement 116, either independently or in combination with the heating member 118, under the low load condition of the gas turbine engine 100, also enables reduction of emission of combustion products with the exhaust gas from the exhaust passage 104, apart from supply low quantity of the inlet air.

In one additional embodiment of the present disclosure, the gas turbine engine 100 may include an exhaust gases flow control arrangement 122. Such exhaust gases flow control arrangement 122 may be adapted to be detachably disposed in the exhaust passage 104 so that when required may be removed. Such exhaust gases flow control arrangement 122 may be adapted to increase pressure and temperature of the exhausted gas exiting from the turbine 110. Specifically, such additional placement of the exhaust gases flow control arrangement 122, apart from that of the inlet air flow control arrangement 116, may be effective in a combined cycle power plants, where the gas turbine engine 100 may have been combined with other power plants, such as a steam/water cycle power plants. In such combined power plants, which may also include a Heat Recovery Steam Generator (HRSG), the exhaust gases flow control arrangement 122 may be adapted to be detachably disposed in the exhaust passage 104, downstream of the HRSG. This ensures the increase in pressure and temperature of the exhausted gas exiting from the turbine 110 for enabling such other power plant to utilize the exhausted gas for being operated. In other words, with such addition of the exhaust gases flow control arrangement 122 in the gas turbine engine 100 and keeping the turbine inlet temperature or power constant, the gas turbine exhaust temperature may be increased, which is in favor when the gas turbine engine 100 is utilized with combined cycle power plant. Additionally, this is also a favorable condition when a fast power ramp-up rate is required in such combined cycle.

In one embodiment of the present disclosure, the inlet air and exhaust gases flow control arrangements 116 and 122 may be one of a shutter arrangement, a grid arrangement, a damper arrangement and a throttle device arrangement selectively chosen per requirement. However, without departing from the scope of the present disclosure, the inlet air and exhaust gases flow control arrangements 116, 122 may be any suitable arrangements, which may perform the controlling inlet air and exhaust gases.

In one additional embodiment of the present disclosure, the gas turbine engine 100 may include a control system 120 adapted and configured to control the inlet air and exhaust gases flow control arrangements 116, 120.

The improved gas turbine engine of the present disclosure is advantageous in various scopes. The improved gas turbine engine of the disclosure are adaptable in terms reducing intake pressure in turn reducing intake mass flow of inlet air while maintaining the volume flow of the intake air without affecting the combustor or combustion chamber operating conditions. The improved gas turbine engine enables reduction of turbine power by lowering the mass flow of the inlet air by utilizing suitable arrangement for achieving low load condition. Further, the improved gas turbine engine is improved in efficiency, and is improved in emission control of combustion products, such as Nitrogen Oxide gases (NOx), Carbon monoxide (CO), Carbon dioxide (CO₂), Unburned Hydrocarbons (UHC) etc., in exhaust gases, at low load condition. Such improved gas turbine engine also enables turbine pressure ratios to be lower than compressor ratio. Further, the improved gas turbine engine is also effect with combined power cycles, where by keeping the turbine inlet temperature constant or keeping the power constant, the gas turbine exhaust temperature will increase which is in favor for other combined cycle power plant, such as water/steam cycles, when a fast power ramp-up rate is required in such combined cycle power plants. Further, the improved gas turbine engine are convenient to use and economical. Various other advantages and features of the present disclosure are apparent from the above detailed description and appendage claims.

The foregoing descriptions of specific embodiments of the present disclosure have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present disclosure to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present disclosure and its practical application, to thereby enable others skilled in the art to best utilize the present disclosure and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present disclosure. 

What is claimed is:
 1. A gas turbine engine of a gas power plant, the gas turbine engine comprising: inlet and exhaust passages the inlet passage adapted to receive and direct inlet air to a compressor to compress and supply the inlet air to a combustor to produce gas to drive a turbine, and the exhaust passage adapted to release exhaust gas from the turbine; a filter member disposed in the inlet passage to filter the inlet air; at least a row of Variable Inlet Guide Vanes (VIGV) adapted to be configured on the compressor; and an inlet air flow control arrangement adapted to be detachably disposed at least: between the filter member and the row of VIGV, and adjacent the filter member, wherein at least one of the VIGV and the air inlet flow control arrangement are configured to be selectively operable and controllable, upon requirement, to at least partially close the inlet passage to modulate and create predetermined required pressure loss in the inlet passage in order to supply reduced amount of the inlet air to the compressor to enable the reduction of power output of the gas turbine engine at a low load condition.
 2. The gas turbine engine as claimed in claim 1, further comprising a heating member adapted to be configured in the inlet passage to heat the inlet air to enable, in combination of pressure loss in the inlet passage, the reduction of power output of the gas turbine engine at the low load condition.
 3. The gas turbine engine as claimed in claim 2, wherein the inlet air flow control arrangement, either independently or in combination with the heating member, under the low load condition of the gas turbine engine, enable reduction of emission of combustion products with the exhaust gas from the exhaust passage.
 4. The gas turbine engine as claimed in claim 1, wherein the inlet air flow control arrangement is adapted to be configured to maintain the direction of flow of the inlet air such downstream of the VIGV receives axial inflow.
 5. The gas turbine engine as claimed in claim 1, wherein the inlet air flow control arrangement is adapted to be configured to change the direction of flow of the inlet air such that incident of the inlet air at the VIGV leading edge is reduced.
 6. The gas turbine engine as claimed in claim 1, wherein the inlet air flow control arrangement is one of a shutter arrangement, a grid arrangement, a damper arrangement and a throttle device arrangement.
 7. The gas turbine engine as claimed in claim 1, further comprising a control system adapted and configured to control the inlet air flow control arrangement.
 8. The gas turbine engine as claimed in claim 1, further comprising an exhaust gases flow control arrangement adapted to be detachably disposed in the exhaust passage to increase pressure and temperature of the exhausted gas exiting from the turbine.
 9. The gas turbine engine as claimed in claim 8, further comprising a control system 120 adapted and configured to control the exhaust gases flow control arrangement.
 10. The gas turbine engine of the gas power plant with a Heat Recovery Steam Generator (HRSG) of claim 8, wherein the exhaust gases flow control arrangement is adapted to be detachably disposed in the exhaust passage, downstream of the HRSG to increase pressure and temperature of the exhaust gas exiting from the turbine.
 11. The gas turbine engine as claimed in claim 1, wherein the exhaust gases flow control arrangement is one of a shutter arrangement, a grid arrangement, a damper arrangement and a throttle device arrangement. 